Antenna device

ABSTRACT

An antenna device, wherein the polarization is improved by an identical antenna or substrate, and a higher gain and a smaller size are provided even when the installation conditions are changed. The antenna includes a base provided with a power feed point electrically connected to a power feed unit in a wireless circuit, an antenna element set up on the base and electrically connected to the power feed point, and a ground pattern provided on the base. The antenna element includes a rise part which rises from the base and an element part extending from the top edge of the rise in any direction in the plane parallel to the base. The ground pattern is divided into at least two ground regions by a boundary, and a ground connection part which electrically and locally connects the ground regions.

TECHNICAL FIELD

The present disclosure relates to an antenna device that can beadvantageously used in a wireless communication technology such as akeyless operation system for an automobile and the like.

BACKGROUND

In recent years, antenna devices using linear elements have beeninvestigated for the purpose of use in wireless communication, such asin a keyless operation system for an automobile. Conventionally, amonopole antenna having a length ¼ that of the working wavelength of theantenna with respect to the ground plane and in which a wire element isdisposed is generally used as an antenna device that uses linearelements. However, because this monopole antenna is large and talloverall, inverted-L antennas have been developed in which this monopoleantenna is folded at an intermediate point to reduce the size andheight.

Furthermore, in this inverted-L antenna, matching a 50Ω power feed lineis very difficult because the reactance, which is determined by thelength of the horizontal portion of the antenna element that is parallelto the ground plane, is the capacitance, and is a large value. Thus,conventionally, in order to facilitate matching between an antennaelement and a 50Ω power feed line, what is referred to as an inverted-Fantenna has been proposed. This inverted-F antenna is one in which astub is provided that connects the ground plane and the radiationelement near the power feed point that is provided at an intermediatelocation on the antenna element. Thereby, the capacitance due to thereactance is neutralized, and matching a 50Ω power feed line isfacilitated. For example, in Japanese Laid-Open Patent Application No.2006-197528, an inverted-F antenna has been proposed that is applied toa folding portable wireless device, and provides an antenna element thatis disposed on a printed wiring substrate and is folded perpendicular toa flexible flat cable that is connected to the printed wiring substrate.In this inverted-F antenna, the antenna element is folded in a verticaldirection with respect to the printed wiring substrate.

However, in the above conventional technology as well, the followingproblems remain. Specifically, in the conventional antenna, in the casein which the various arrangement conditions are to be changed, thepolarization (vertical and horizontal polarization) is designed withrespect to the principal polarization as required by the use conditions,and due to being dependent thereon, handling polarization improvementsusing the same antenna profile is difficult. Thus, methods in whichdesign changes are made to the antenna profile in order to improvepolarization have been considered, but there are limits to designchanges due to dependency on the size of the case and there arefrequently difficulties in terms of the cost of producing metal moldsand the like. Thus, a method in which a metal plate is disposed tochange the polarization forcibly has been considered, but there thedrawbacks that directionality is limited, antenna characteristicsdeteriorate, and the polarization cannot be easily improved.

In addition, in the case of the technology disclosed in JapaneseLaid-Open Patent Application No. 2006-197528, the characteristics areimproved by folding the element in a length or width direction withrespect to a flexible cable, but because the improvements incharacteristics are dependent on the surrounding environment, thepolarization and directionality cannot be improved, and downsizing andincreasing the thinness are difficult. From the above point of view, inthe case in which the arrangement conditions are changed in theconventional technology, in the same antenna, substrate, and case, thereare the drawbacks that improving the polarization, obtaining high gain,downsizing, and increasing thinness are difficult.

SUMMARY

In consideration of the above described problems, it is an object of thepresent disclosure to provide an antenna device that improves thepolarization of the same antenna and substrate and the like and canrealize a high gain and downsizing even in the case in which thearrangement conditions change.

The present disclosure uses the following structure to solve theproblems described above. Specifically, the antenna device of thepresent disclosure provides a first ground area on which a power feedcomponent that is electrically connected to the power feed point of awireless circuit is provided and that is formed by a conductor; a secondground area that is provided along the outer periphery of the firstground area so as to exclude a portion of the periphery thereon and thatis formed by a conductor; a boundary between the first ground area andthe second ground area; an antenna element that is electricallyconnected to the power feed point and is erected on the first groundarea; and a ground connection component that locally electricallyconnects the first ground area and the second ground area. The antennaelement is characterized in providing a raised component that rises fromthe first ground area and an element component that extends directlyabove the second area from the raised component.

Because this antenna device provides a ground connection component thatlocally electrically connects the first ground area and the secondground area, and the antenna element includes a raised component thatrises from the first ground area and an element component that extendsdirectly above the second ground area from the upper end portion of therising area, high frequency current (current distribution) that flows tothe antenna element, the first ground area, and the second ground areacan be adjusted depending on the local connection position, and thepolarization of the antenna overall can be improved. That is, a groundarea that is divided into a plurality of parts is provided, and thecharacteristics of the desired polarization can be improved withoutchanging the antenna element based on the dispositional relationshipbetween these ground elements and the antenna element.

Note that the above term “boundary” denotes (electrically divided)portions at which the first ground area and the second ground area arenot electrically connected. Specifically, this “boundary” is an area orspace at which the conductor of the first ground area and the conductorof the second ground area are not linked together, and denotes anelectrically insulated range that is interposed between the first groundarea and the second ground area.

In addition, providing the above “locally electrically connected groundconnection component” denotes that there is a location (the groundconnection component) that electrically connects the first ground areaand the second ground area by crossing over the “boundary”.

In addition, the antenna device of the present disclosure provides asubstrate on which a ground pattern that is divided into the firstground area and the second ground area is provided.

A ground pattern that is provided on a substrate frequently naturallyhas large in size and is integrated from the viewpoint of improving theantenna gain. Thus, in the present disclosure, because a boundary forefficiently dividing the ground pattern of the substrate for the antennaelement is provided and the frequency current flowing to the antennaelement and the ground pattern is adjusted, the polarization of theantenna overall can be improved by making an efficient connectionmethod.

In addition, the antenna device of the present disclosure provides afirst substrate on which the first ground area is provided and a secondsubstrate on which the second ground area is provided, and the firstsubstrate and the second substrate are disposed such that the boundaryis interposed therebetween.

Specifically, in this antenna device, because the first substrate andthe second substrate are disposed such that the boundary is interposedtherebetween, by providing the first ground area and the second groundarea on separate substrates, an arrangement becomes possible in whichone can be easily be replaced with another having a separate shape. Forexample, by using a general use substrate for one and using areplacement substrate for the other, a variety of shapes can be easilyused.

In addition, in the antenna device of the present disclosure, theboundary is perpendicular to the element component at least at onelocation in a plan view from above the first ground area and the secondground area. Specifically, in this antenna device, because the boundaryis perpendicular to the element component at least at one location in aplan view from above the first ground area and the second ground area,the current distribution can be most effectively adjusted.

In addition, in the antenna device of the present disclosure, theboundary divides the first ground area and the second ground area inproximity to the power feed point. Specifically, in this antenna device,because the boundary divides the first ground area and the second groundarea in proximity to the power feed point, a current distribution can bemore robustly adjusted.

In addition, in the antenna device of the present disclosure, the groundconnection component is provided at a proximate position near the powerfeed point. Specifically, in this antenna device, because the groundconnection component is provided at a proximate position near the powerfeed point, when the principal polarization is made the horizontalpolarization, the effect of the improvement of the horizontalpolarization can be more robustly obtained.

In addition, in the antenna device of the present disclosure, the groundconnecting component is provided at a distant position most separatedfrom the power feed point. Specifically, in this antenna device, becausethe ground connecting component is provided at a distant position mostseparated from the power feed point, when the principal polarization isvertical polarization, the effect of the improvement of the verticalpolarization can be more robustly obtained.

In addition, in the antenna device of the present disclosure, the groundconnection component is provided at an intermediate position on theboundary. Specifically, in the antenna device, because the groundconnection component is provided at an intermediate position on theboundary, in the case in which both horizontal polarization and thevertical polarization are necessary, the effect of a significantimprovement of both polarizations can be obtained.

According to the present disclosure, the following effects are exhibited

According to the antenna device of the present disclosure, because aground connection component that locally electrically connects the firstground area and the second ground area is provided, and the antennaelement includes a raised component that rises from the first groundarea and an element component that extends directly above the secondground area from the upper end portion of the raised component, the highfrequency current that flows to the antenna element, the first groundarea, and the second ground area can be adjusted depending on the localconnection position, and the polarization of the antenna overall can beimproved. Specifically, even in the case in which the arrangementconditions are changed, based on the dispositional relationship betweenthe above connection positions and the antenna element, the polarizationcan be improved, and increased gain and downsizing can be realizedwithout changing the antenna element. Therefore, the antenna device ofthe present disclosure is advantageous for any wireless communicationsystem that is mounted on a vehicle or the like, and in particular, areception antenna device, a transmission antenna device, or atransmission and reception antenna device used in a wireless operationsystem.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simple plan view that shows the antenna device of a firstembodiment of the antenna device of the present disclosure;

FIG. 2 is a simple perspective view that shows the antenna device of thefirst embodiment;

FIG. 3 is an explanatory drawing using an equivalent circuit that showsthe antenna device of the first embodiment;

FIG. 4 is a graph that shows, in a first embodiment, a radiation patternin the case in which the ground connection component is provided at aproximate position near the power feed point in the first embodiment;

FIG. 5 is a graph that shows, in the first embodiment, a radiationpattern in the case in which the ground connection component is providedat a distant position far from the power feed point;

FIG. 6 is a graph that shows, in the first embodiment, a radiationpattern in the case in which the ground connection component is providedat an intermediate position on the boundary;

FIG. 7 is a graph that shows, in a first embodiment, the radiationpattern in the case in which the ground connection component is providedat three locations: at a proximate position near the power feed point,at a distant position far from the power feed point, and an intermediateposition on the boundary;

FIG. 8 is a graph that shows, in a first embodiment, a comparison ofmaximum gain for horizontal polarization and vertical polarization forthe arrangement positions of the ground connection components; and

FIG. 9 is a simple plan view that shows an antenna device of a secondembodiment of the antenna device according to the present disclosure.

DETAILED DESCRIPTION

Below, a first embodiment of the antenna device according to the presentdisclosure will be explained with reference to FIG. 1 to FIG. 8.

The antenna device of the present embodiment is a wireless communicationsystem that is mounted, for example, in an automobile or the like, andin particular, is a reception antenna device, a transmission antennadevice, or a transmission and reception antenna device used in a keylessoperation system. As shown in FIGS. 1 to 3, the antenna device providesa first ground area 5A on which a power feed point 1 that iselectrically connected to a 50Ω power feed line (power feed component ofthe wireless circuit; not illustrated) and is formed by a conductor suchas copper foil or the like; a second ground area 5B that is formed by aconductor such as copper foil or the like along the outer periphery ofthe first ground area 5A so as to exclude a portion thereof; a boundary7 between the first ground area 5A and the second ground area 5B; anantenna element 3 that is electrically connected to the power feed point1 and is erected above the first ground area 5A; and a ground connectioncomponent 6 that locally electrically connects the first ground area 5Aand the second ground area 5B.

In addition, the antenna device provides a substrate 2 on which a groundpattern 5 is provided, which is divided in to the first ground area 5Aand the second ground area 5B; and a matching circuit component 4, whichis electrically connected to the power feed point 1 and the antennaelement 3, provided on the substrate 2, and that matches the reactanceof the antenna element 3 and the power feed line.

Specifically, this antenna device provides a substrate 2 on which apower feed point 1, to which a 50Ω power feed line (not illustrated) iselectrically connected, is provided; an antenna element 3 that iselectrically connected to the power feed point 1 and is erected on thesubstrate 2; a matching circuit component 4 that is electricallyconnected to the power feed point 1 and the antenna element 3, erectedon the substrate 2, and matches the reactance of the antenna element 3and the power feed line; and a ground pattern 5 that is provided on thesubstrate 2.

Note that the key operation system described above denotes a system thatenables the locking or unlocking operation (what is referred to as a“keyless entry system”) of the doors or tailgate and the like of anautomobile and the startup of an engine and the like by carrying out acheck of an ID code by wireless communication between the key and thereceiving antenna device arranged on automobile main body side when adriver or the like simply approaches the vehicle within a wirelessoperation range carrying a key that is referred to as a “keylessoperation key” and that has a wireless communication function.

The substrate 2 is, for example, a wired substrate or a circuitsubstrate, and a wireless communication circuit or an electronic controlunit (ECU) or the like (not illustrated) including the matching circuitcomponent 4, are formed on the upper surface and the lower surfacethereof. Note that the antenna element 3 may also be installed on a sideopposed to the surface on which the electronic control unit of thesubstrate 2 is mounted.

The antenna element 3 is formed by a conductive material such as copperwire, copper-clad wire, copper alloy wire (for example, brass) aluminumwire, aluminum-clad wire, or aluminum alloy wire or the like, having alength that is ¼ or another integer fraction of that of the antennaworking wavelength, and the thickness of the wire is set according todesired characteristics. In addition, the shape of the wire may be across-sectional profile of a circle, rectangle, or polygon or the like.In consideration of bending, a circular cross-section is preferable.

In addition, the antenna element 3 may be covered by an insulating layeron the outer periphery of the conducting materials (wire) describedabove.

This antenna element 3 includes a raised portion 3 a that rises from thefirst ground area 5A and an element component 3 b that extends directlyabove the second ground area 5B from the upper end portion of the raisedportion 3 a.

Specifically, this antenna element 3 includes a raised portion 3 a thatrises from the substrate 2, and an element 3 b that bends from the upperend portion of the raised portion 3 a and extends in an arbitrarydirection within a plane parallel to the substrate. The elementcomponent 3 b of the present embodiment is an open element that bends orcurves back at an intermediate portion after extending in a direction ina plane parallel to the substrate 2 from the upper end portion of theraised portion 3 a, and forms substantially square-C shape that extendsalong a direction opposite to the first direction.

Note that the element component 3 b may extend in an arbitrary directionafter extending directly over the second ground area 5B from the firstground area 5A, but from the point of view of ease of formation of theantenna and stability of the antenna characteristics, as explainedabove, the element component 3 b is formed so as to extend in anarbitrary direction in a plane parallel to the substrate 2.

As described above, the ground pattern 5 is divided into the firstground area 5A and the second ground area 5B at the boundary 7, which isa separation line on the substrate 2, and at the same time, includes aground connecting portion 6 that locally electrically connects theseground areas 5A and 5B. In the present embodiment, the ground pattern 5is divided into the first ground area 5A for analogue circuits and asecond ground area 5B for digital circuits. In this ground pattern 5,the second ground area 5B is arranged along the outer periphery firstground area 5A so as to exclude a portion (the upper edge side and theright edge side in FIG. 1) of the outer periphery. Specifically, thesecond ground area 5B is disposed so as to leave open and not completelysurround at least one portion of the outer periphery of the first groundarea 5A. Note that in the case in which the ground pattern 5 is dividedat a plurality of locations, it is desirable that as large an area aspossible for each of the ground areas 5A and 5B be ensured.

The boundary 7 is a line shaped or band shaped non-patterned portionthat electrically divides the ground pattern 5 into the first groundarea 5A and the second ground area 5B, except at a portion locallyelectrically connected by the ground connecting portion 6.

In addition, the first ground area 5A and the second ground area 5B aredivided by the boundary 7 into such shapes as shown in FIG. 1 inconformity to the shape of the substrate 2. However, for example, thesecond ground area 5B may be divided into an alternative shape such as arectangle by the boundary 7.

The boundary 7 intersects the element component 3 b in a plan view fromabove the first ground area 5A and the second ground area 5B. Inparticular, the boundary 7 is perpendicular to the element component 3 bin a plan view from above the first ground area 5A and the second groundarea 5B at least at one location, and the ground pattern 5 is divided inproximity to the power feed point 1. In the present embodiment, in aplan view, the boundary 7 is perpendicular to the substantially C-shapedelement component 3 b at two at locations.

The matching circuit component 4 is a circuit structure including aπ-type LC circuit formed by a plurality of inductors L or capacitors Cor a T-type circuit at a single stage or a plurality of stages betweenthe power feed point 1 and the antenna element 3. This matching circuitcomponent 4 has the function corresponding to a portion that achievesmatching from the power feed point to the stub in a conventionalinverted-F antenna.

The ground connecting portion 6 is provided at least at one locationdepending on the necessary polarization, and, for example, in the casethat the principal polarization is horizontal polarization, the groundconnecting portion 6 is provided at a proximate position 6A near thepower feed point 1, and in the case in which the principal polarizationis vertical polarization, the ground connecting portion 6 is provided ata distant location 6B most separated from the power feed point 1.Furthermore, in the case in which both horizontal polarization andvertical polarization are necessary, the ground connecting portion 6 isprovided at an intermediate position 6C along the boundary 7.

Note that the terms “proximate” and “distant” with respect to theconnection position of the ground connection component 6 denotedistances from the power feed point 1 that is electrically connected tothe antenna element 3 on the boundary 7.

In addition, passive elements such as generally used resistors,capacitors, and inducers and the like are used at the ground connectingportion 6.

Note that by using a variable resistor, a variable capacitor, or avariable inducer or the like as the ground connecting portion 6,flexible adjustment also becomes possible. In addition, a groundconnecting portion 6 such as copper file or the like may be used.

Next, the results of measuring actual polarization and directionality ofthe antenna device of the present embodiment by varying the position ofthe ground connecting portion 6 for will be explained.

First, FIG. 4 shows the result of measuring the radiation pattern forthe case in which the ground connection component 6 is provided at theproximate location 6 near the power feed point. As can be understoodfrom this result, advantageous results are obtained for a radiationpattern whose principal polarization is horizontal polarization, has atoroidal directionality, and has a maximum gain of −11.63 dBi. Inaddition, here the maximum gain of the vertical polarization is a lowvalue of −28.13 dBi.

In addition, FIG. 5 shows the result of measuring a horizontal radiationpattern of substrate 2 for the case in which the ground connectioncomponent 6 is provided at the distant position 6B far from the powerfeed point 1. As can be understood from this result, the principalpolarization of the radiation pattern is vertical polarization, andthus, the principal polarization changes in comparison to the case inwhich the ground connection component 6 is provided at the proximateposition 6A. Note that the horizontal polarization having a toroidaldirectionality remains as-is, but the maximum gain becomes −19.28 dBi.In addition, in contrast, the maximum gain of a vertical polarization,which is the principal polarization, is −15.01 dBi, and a high gain of13 dB is obtained in comparison to the case in which the groundconnection component 6 is provided at the proximate position 6A.

In addition, FIG. 6 shows the result of measuring the radiation patternfor the case in which the ground connection component 6 is provided atthe intermediate position 6C of the boundary 7. As can be understoodfrom this result, the vertical polarization and the horizontalpolarization of the radiation pattern are both substantially identical,and a directionality of −17 dBi is obtained at the maximum gain.

In this manner, for the same antenna element 3, simply by changing onlythe connection position of the ground areas 5A and 5B, the polarizationcan be improved by adjusting the gain of the vertical polarization, thehorizontal polarization, or both polarizations

Note that FIG. 7 shows the results of measuring the radiation patternfor the case in which the ground connection component 6 is connected atall three locations, that is, the above proximate position 6A, thedistant position 6B, and the intermediate position 6C. As can beunderstood from these results, the polarization obtaining the maximumgain, that is, the horizontal polarization when electrically connectedat the proximate position 6A shown in FIG. 6, has a toroidaldirectionality and a maximum gain of −11.63 dBi, and thus, hascharacteristics similar to the state shown in FIG. 4. However, whencompared to the radiation pattern in FIG. 4, an advantageous result isobtained in which the vertical polarization is improved and the maximumgain is −21.02 dBi. That is, by combining the connection positions ofthe ground areas 5A and 5B (the arrangement positions of the groundconnection components 6), the high frequency current (currentdistribution) flowing to the antenna element 3 and the ground pattern 5can be adjusted, and the polarization of the antenna overall can beimproved.

In addition, as quantitative evidence, a comparison of maximum gain isshown in FIG. 8. This is the result of extracting the maximum gain foreach of the horizontal and vertical polarizations for each of theradiation patterns from FIG. 4 to FIG. 6 and comparing the positions ofthe ground connection component 6. As can be understood from thisresult, the horizontal polarization deteriorates as the position of theground connection component 6 becomes more distant from the power feedpoint 1, and the vertical polarization improves as the position of theground connection component 6 becomes more distant from the power feedpoint 1. This means that the position of the ground connection component6 is provided at the proximate position 6A near the power feed point 1when the principal polarization is to be the horizontal polarization;the ground connection component 6 is provided at the distant position 6Bfar from the power feed point 1 in the case in which the principalpolarization is to be the vertical polarization; and furthermore, theposition of the ground connection component 6 is provided at theintermediate point 6C of the boundary in the case in which bothpolarizations are necessary. Thereby, the polarization can be improved.Note that FIG. 8 is the result comparing the radiation pattern of thehorizontal plane of the substrate 2, but in the case of the radiationpattern of the other planes, the relationships in FIG. 8 are reversed.

In this manner, the antenna device of the present embodiment provides aground connection component 6 that locally electrically connects thefirst ground area 5A and the second ground area 5B, and the antennaelement 3 includes a rising area 3 a that rises from the first groundarea 5A and an element component 3 b that extends directly above thesecond ground area 5B from the upper end portion of the rising portion 3a. Thus, the high frequency current (current distribution) that flows tothe antenna element 3 and the ground pattern 5 (first ground area 5A andsecond ground area 5B) can be adjusted depending on the local connectionposition, and the polarization of the antenna overall can be improved.This means that plural divided ground areas 5A and 5B are provided, andbased on the positional relationships between the connection positionsthereof and the antenna element 3, the characteristics of the desiredpolarization can be improved without changing the antenna element 3.

Frequently, the size of the ground pattern 5 provided on the substrate 2was naturally made large and integrated in consideration of improvingthe antenna gain. Thus, in the present embodiment, a boundary 7 forefficiently dividing the ground pattern 5 of the substrate 2 withrespect to the antenna element 3 is provided, and in order to adjust thehigh frequency current that flows to the antenna element 3 and theground pattern 5, the polarization of the antenna overall can beimproved by an efficient connection method.

In addition, because the boundary 7 is perpendicular to the elementcomponent 3 b in a plan view from above the first ground area 5A and thesecond ground area 5B at least at one location, the current distributioncan be adjusted most effectively.

Furthermore, because the boundary 7 divides the ground pattern 5 inproximity to the power feed point 1, the current distribution can beadjusted more robustly.

In addition, when the ground connection component 6 is provided at aproximate position near the power feed point 1, in the case in which theprinciple polarization is horizontal polarization, the effect of animprovement in characteristics can be more robustly obtained.

In addition, when the ground connection component 6 is provided at adistant position most separated from the power feed point 1, in the casein which the principal polarization is vertical polarization, the effectof an improvement in vertical polarization can be more robustlyobtained.

In addition, when the ground connection component 6 is provided at anintermediate position of the boundary 7, in the case in which both thehorizontal polarization and the vertical polarization are necessary, theeffect of an improvement in both polarizations can be more robustlyobtained.

Next, a second embodiment of the antenna device according to the presentdisclosure will be explained with reference to FIG. 9. Note that in thefollowing explanation of the embodiment, identical structural componentsexplained in the above embodiment have appended identical referencenumeral, and the explanation thereof is omitted.

The point of difference between the second embodiment and the firstembodiment is that in the first embodiment a first ground area 5A and asecond ground area 5B that are divided from each other on one substrate2 by the boundary 7 are formed, whereas in contrast, the antenna deviceof the second embodiment, as shown in FIG. 9, provides a first substrate22A on which the first ground area 25A is provided and a secondsubstrate 22B on which a second ground area 25B is provided, and thefirst substrate 22A and the second substrate 22B are provided such thatthe boundary 27 is interposed therebetween.

The antenna device of this second embodiment provides a square shapedfirst substrate 22A and a recessed second substrate 22B that is arrangedalong the other three edges excluding one edge on the outer periphery ofthe first substrate 22A. Specifically, the antenna device of the secondembodiment provides a square first ground area 25A formed on the firstsubstrate 22A and a recessed second ground area 25B that is formed onthe second substrate 22B along the outer periphery of the first groundarea 25A so as to exclude a portion of the outer periphery thereof.

Therefore, the boundary 27 that divides the first ground area 25A andthe second ground area 25B is not a dividing line on the substrate, butrather is a gap area between the first substrate 22A and the secondsubstrate 22B.

In this manner, in the second embodiment, because the first substrate22A and the second substrate 22B are disposed so as to surround theboundary 27, by providing the first ground area 25A and the secondground area 25B on separate substrates, an arrangement in which one iseasily replaced by another having a different shape becomes possible.For example, by making one a general-use substrate and making the othera replacement substrate, a variety of shapes can be easily used.

Note that the present disclosure is not limited by the embodimentsdescribed above, but various modifications can be added within a rangethat does not depart from the spirit of the present disclosure.

For example, in the first embodiment, a ground pattern 5 is formed onthe surface of a substrate 2, but there are cases in which a multilayersubstrate is used as a substrate when designing an actual wirelesscircuit. In this case, the ground pattern 5 may be designed on anylayer, such as an inner layer pattern. Note that ideally, the groundpattern 5 is designed on a component surface or solder surface of thesurface of the substrate.

In addition, the antenna element 3 was formed by a conducting line madeby a copper wire or the like, but the antenna element 3 may be formed byother conductors. For example, an antenna element that has been stampedon a metal plate and formed into a band (the cross-sectional profilebeing rectangular) may be formed.

1. An antenna device comprising: a first ground area in which a powerfeed point that is electrically connected to a power feed portion of awireless circuit is provided and that is formed by a conductor; a secondground area that is provided along the outer periphery of the firstground area so as to exclude a portion of the periphery thereof and thatis formed by a conductor; a boundary between the first ground area andthe second ground area; an antenna element that is electricallyconnected to the power feed point and is erected on the first groundarea; and a ground connection component that locally electricallyconnects the first ground area and the second ground area, wherein theantenna element includes a raised portion that rises from the firstground area and an element component that extends above the secondground area from the upper end portion of the raised portion.
 2. Anantenna device according to claim 1, further comprising a substrate thatprovides a ground pattern divided into the first ground area and thesecond ground area.
 3. An antenna device according to claim 1, furthercomprising: a first substrate on which the first ground area isprovided; and a second substrate on which the second ground area isprovided, wherein the first substrate and the second substrate arearranged such that the boundary is interposed therebetween.
 4. Anantenna device according to claim 1, wherein the boundary isperpendicular to the element component in a plan view from above thefirst ground area and the second ground area at least at one location.5. An antenna device according to claim 1, wherein the boundaryseparates the first ground area and the second ground area in proximityto the power feed point.
 6. An antenna device according to claim 1,wherein the ground connection component is provided at a proximateposition near the power feed point.
 7. An antenna device according toclaim 1, wherein the ground connection component is provided at adistant position most separated from the power feed point.
 8. An antennadevice according to claim 1, wherein the ground connection component isprovided at an intermediate position on the boundary.